Rotary distributor switch for internal combustion engine



Dec 2, 1969 P. J. clAcclA ROTARY DISTRIBUTOR SWITCH FOR INTERNAL COMBUSTION ENGINE Filed April 1, 1968 l/IIIIIIII INYENTOR. ('accuz 17a/fiera, Ware @m/s T FR/YW United States 3,482,065 ROTARY DISTRIBUTOR SWITCH FOR INTERNAL COMBUSTION ENGINE Patrick I. Ciaccia, Westport, Conn., assignor of forty-two percent to Patrick J. Ciacca, Westport, Conn., twentynine percent each to Douglas F. Linsley, Westport,

Conn., and Earl Swebilius, Clinton, Conn.

Filed Apr. 1, 1968, Ser. No. 717,728 Int. Cl. H01h 39/00, 19/00 U.S. Cl. 200--24 8 Claims ABSTRACT OF THE DISCLOSURE A group of electrically connected rst contacts is arranged in a circle about the distributor shaft, and are energized through the primary winding of the ignition coil. A second contact is mounted on the distributor rotor and grounded through the distributor shaft. The second contact is resiliently urged toward the rst contacts to repeatedly complete the primary circuit as it successively engages and is detiected by the first contacts. The contacts may be provided with a ramp to reduce contact bouncing. A further second contact and a further cooperating circle of first contacts may be provided.

The invention relates to an ignition primary circuit switch for energizing the ignition coil primary winding in an internal combustion engine. More particularly, it relates to such a switch wherein a plurality of electrically connected rst contacts are mounted on a lirst member and arranged in a circle about a distributor shaft for cooperation with a second contact mounted on a second member, with one of the members rotating with the distributor shaft.

Conventional ignition primary switches are in the form of a fixed contact mounted beside the distributor shaft for cooperation with a movable contact resiliently urged toward the rst contact by a leaf spring. A rubbing block or cam follower on the spring engages a multi-lobed cam on the distributor shaft, to control operation of the switch. This system has a number of disadvantages. Wear of the rubbing block changes the length of the period when the switch is closed (the dwell angle), as well as changing the relationship between the occurrence of the spark and crankshaft position (ignition timing). Therefore the timing must be checked when the contacts are replaced or adjusted. Such contacts are subject to pitting and burning in use, increasing the resistance in the primary circuit and causing diiiiculty in starting the engine, loss of power, etc.

One proposed means for avoiding these problems is disclosed in U.S. Patent 2,766,338 to Jamieson, wherein a stationary brush is resiliently urged into contact with a rotating disc having conductive segments thereon. A further similar approach is discussed in U.S. Patent 2,986,- 611 to DeRugeris. Each of these devices provides a marked advance over the conventional cammed ignition contacts, since they provide accurate dwell angle and timing. However, these approaches are relatively expensive and require substantially complete rebuilding of the distributor. Since the sliding contacts bear on different materials, differential wear becomes a problem in actual service. Furthermore, these structures do not provide for ignition advance and are subject to other disadvantages.

Accordingly, a primary object of the invention is to provide an ignition primary switch wherein the dwell angle and timing are constant.

A further object is to provide a switch of the above character wherein provision is made for spark advance.

A further object is to provide a switch of the above character wherein contact resistance is minimized.

3,482,065- Patented Deaz, 1969 ICC A further object is to provide a switch of the above character which employs a highly eicient wiping action.

A further object is to provide a switch of the above character wherein problems arising -from differential wear are substantially reduced.

A further object is to provide a switch of the above character particularly adapted for high speed operation.

A further object is to provide a switch of the above character which is simple and inexpensive, while being reliable in operation.

Other and more specic objects will be apparent from the features, elements, combinations and operating procedures disclosed in the following detailed description and shown in the drawings.

FIGURE 1 is an exploded perspective view, partially broken away, showing a rst embodiment of the invention;

FIGURE 2 is a side elevation view of the distributor rotor shown in FIGURE l, partially broken away;

FIGURE 3 is a rear elevation view of the FIGURE 2 rotor;

FIGURE 4 is an elevation view, partly broken away, of an alternative embodiment of the contacts shown in FIGURE 1; and

FIGURE 5 is a schematic plan view of an alternative embodiment, wherein the multiple contacts are arranged in concentric circles.

Referring generally to FIGURE l, the invention is illustrated as applied to a conventional distributor including housing 20 into which distributor shaft 22 extends. Rotor 24 is keyed to the upper end of shaft 22 for rotation therewith. A convention distributor cap 26 (only a portion of which is shown) sits on top of housing 20 over rotor 24, and may include the usual central terminal connected to the high voltage ignition coil output terminal, and the usual plurality of terminals arranged in a circle about the central terminal and connected to individual spark plugs. As rotor 24 rotates, blade 28 on its upper surface sequentially connects the central cap terminal to the several other cap terminals. The distributor also preferably includes the -usual spark advance plate 30, the position of which can be shifted by engine vacuum or speed (by means not shown). The apparatus as thus far described is entirely conventional and is almost universally used in modern automobiles. According to the invention, the low voltage contacts which control energization of the ignition coil primary winding are replaced by a novel switch including disc 32 and contact assembly 34, one of which is grounded and the other energized through the ignition coil primary winding.

Referring to FIGURES 1 3, disc 32 is mounted on spark advance plate 30 by insulating screws 36 extending through disc 32 and threaded into plate 30. Insulating sleeves 38 around screws 36 and between plate 30 and disc 32 maintain the proper spacing between plate 30 and disc 32. Accordingly, when plate 30 pivots about shaft 22 a predetermined number of degrees in response to the spark advance mechanism, disc 32 is carried through the same pivotal movement.

Disc 32 may be formed of steel, and has on its upper surface a plurality of button-like contacts 40, there being one contact 40 for each cylinder of the engine. Contacts 40 protrude from the upper side of disc 32 a given distance, and are equally spaced apart on a circle of given radius centered on the axis of shaft 22.

In a specific application for a particular 6-cylinder American car, contacts 40 were circular in plan, having diameters of 0.427 inch and thicknesses of 0.094. Their -lower surfaces were welded to disc 32, while the regions where their at upper surfaces joined their cylindrical side surfaces were rounded with a radius of 0.0625 inch. Con- 3 tacts 40 were equally spaced on a circle having a radius of 1.031 inches.

Contact assembly 34 includes a similar contact button 42 attached to the lower free end of leaf spring 44 by rivet 46. The upper end of leaf spring 44 is secured by screw 48 to the rear portion of rotor 24, so that contact 42 is positioned at the given radius from the axis of shaft 22. Screw 48 also extends through and secures insulating block 50 to the lower rear surface of rotor 24. As best shown in FIGURES 2 and 3, an electrical connection is made through conductor 52 to screw 54, which extends upwardly through block 50 and rotor 24. One end of conductive spring 56 bears on screw54, while the remaining end extends radiallyv inwardly toward shaft 22 and resiliently urges a small metal pin 58 into contact with shaft 22. Since shaft 22 is grounded, an electrical connection is therefore provided between contact 42 and ground. Contact 42 may be identical 4toconta'cts 40.

An insulating shoe 60 (made, for example, of polytetrafluoroethylene) is also secured by rivet 46 to the -lower end of spring 44, and spanscontacts 42 and 40. The lower ends of shoe 60 ride on the surface of disc 32 under the urging yof leaf spring 44 as rotor 24 rotates, and prevent contact 42 from touching disc 32. The dimension's of shoe 60 are selected so that the lower surface of contact 42 is somewhat nearer disc 32 than the upper surfaces of contacts 40, preferably approximately 0.028 nearer when using the above specifically disclosed contacts. Accordingly, as rotor 24 rotates, the leading edge of contact 42, engages the leading edge of each of the contacts 40 in succession7 and contact 42 will be deected upwardly as it passes each contact 40. This provides a sliding or wiping contact action and prevents build up of high resistance residues on the contacts.

An alternative embodiment of the invention is illustrated in FIGURE 4, wherein provision is made for improved operation at high speeds. As shown therein, the leading edge 62 of contact 42 is tapered upwardly to deiine a ramp. As illustrated, the leading edge 64 of contact 40 may tbe beveled to provide a ramp, in addition to or instead of ralmp 62 on contact 42. The provision of at lesat one ramp reduces contact bounce and provides smoother, more reliable operation, particularly at high speeds.

FIGURE illustrates a further modification which is of particular utility at high speed operation. As shown in FIGURE 5, contacts 40 may be arranged in two concentric circles about the axis of shaft 22, with each contact 40 being equally spaced from the two nearest adjacent contacts in the other circle. In this embodiment, separate contact assemblies 34 (which may be identical to the one disclosed in FIGURES 1-3) are provided for cooperation with the two circles of contacts 40. The separate contact assemblies 34 are mounted on rotor 24 and can independently move as they engage and slide over their respective contacts 40. This permits assemblies 34 effectively twice as much time to be returned to their lowermost positions by their leaf springs 44.

In the several embodiments as above described, the dwell angle ignition timing will remain substantially constant once the apparatus has been properly installed. Since contacts 40 and 42 are preferably formed of tungsten carbide, wear is minimized. It should be particularly noted that these 'contacts do not rub against any other material, thus effectively preventing problems arising from more rapid wear of one contacted material than of another contacted material. Since the preferred embodiments of the invention use most of the parts of a conventional distributor (only the rotor need be modified in addition to `disc 32), the cost of conversion is minimized.

While the objects of the invention are efficiently achieved by the preferred forms of the invention described in the foregoing specification, the invention also includes changes and variations falling within and between the definitions of the following claims.

Iclaim:

1. In an internal combustion engine distributor in'- cluding a housing, a distributor shaft, and a rotor on said shaft within said housing for distributing high voltage pulses from the secondary winding of an ignition coil to a series of spark plugs, a switch for supplying lowvoltage pulses through the primary winding of said ignition coil, said switch comprising:

(A) first means including a generally planar disc supporting a first plurality of first contacts in a plane perpendicular to the axis of said shaft, said rst contacts protruding a given distance from one side of said disc, said first contacts being equally spaced from one another on a given circle concentric with said shaft and being electrically connected together; and

(B) second means supporting a second contact at a distance from said shaft equal to the radius of said given circle, said second means including a shoe attached to said second contact and slidably engaging said disc alongside said tirst contacts for normally spacing said second contact from said disc a distance less than said given distance;

(C) one of said first and said second means being mounted on said shaft for rotation therewith While the other of said first 'and said second means remains relatively stationary;

(D) said second means including means resiliently urging said second contact toward said plane, whereby said second contact .sequentially engages said first contacts as said shaft rotates.

2. The switch defined in claim 1, wherein a ramp is included on the leading edge of at least one of (A) said second contact and (B) the contacts of said plurality of rst contacts.

3. The switch defined in claim 1, wherein said second means includes said rotor.

4. The switch defined in claim 3, wherein said second contact is electrically connected to said distributor shaft.

5. The switch deneid in claim 1, wherein said contacts are made of tungsten carbide.

6. The switch defined in claim 1, wherein the dimensions of said shoe are selected so that said second contact will be deected between 0.005 and 0.060 inch by said first contacts as said shaft rotates.

7. The switch dened in cl-aim 1, wherein said other of said iirst and said second means is mounted on a spark advance mechanism.

8. The switch defined in claim 1, further comprising:

(A) a further like plurality of first contacts equally spaced from one another on a further circle of different radius,

(1) said further circle being concentric with said given circle;

(2) each contact of said further plurality being equally spaced from the nearest adjacent contacts of said rst plurality; and

(B) 1a further second contact independently supported on said secon-d means at a distance from said shaft equal to the radius of said further circle and resilientlybiased toward said disc for cooperation said further plurality of first contacts.

References Cited UNITED STATES PATENTS 2,766,338 10/ 1956 Jamieson et al. 200-24 2, 847,523 8/ 1958 Van A-melsfort.

3,226,495 12/ 1965 Selci.

3,260,805 7/1966 Pihl.

ROBERT K. SCHAEFER, Primary Examiner J. R. SCOTT, Assistant Examiner U.S. Cl. X.R. 200-28 

